Spring piece



Jan. 12, 1943. O. QJBARNETIJ 2,308,042

sauna PIECE Filed June 4, 1941 2 Sheets-Sheet l I ll Inventor Ola 'ver C Barn eff A Home) Jan. 12, 1943. 0. C. BARNETT v2,308,042

SPRING PIECE Filed June 4, 1941 2 Sheets-Sheet 2 Oliver 6'- Ba/rwe ZZ A tlorney Iuventor Patented Jan. 12, 1943 SPRING PIECE Oliver C. Barnett, Punxsutawney, Pa., assignor to Hoffman Brothers Drilling 00., Punxsutawney, Pa., a corporation of Pennsylvania Application June 4;, 1941, Serial No. 396,633- 6 Claims. (01. 255-72) My invention relates generally to improvements in core drilling and recovering apparatus, and more particularly to an improved core trap, or

- spring piece, especially adapted although not restricted to the recovery in unimpaired condition of cores from formations of relatively soft coal which are otherwise diflicult to recover, and the primary object of my invention is to provide a core trap or spring piece of the character indicated which is relatively simple in construction and is easily applied and used.

Other important objects and advantages of my invention will appear in the following description and the appended drawings, wherein for purposes of illustration I have shown a preferred embodiment.

In the drawings:

Figure 1 is a contracted side elevational view of core drilling apparatus in accordance with the present invention.

Figure 2 is a fragmentary enlarged transverse vertical sectional view taken along the line 2-2 of Figure 1.

Figure 3 is an enlarged transverse vertical sectional view taken along the line 33 of Figure 2.

Figure 4 is a horizontal sectional view taken along the line 4-4 of Figure 3.

Figure 5 is a transverse vertical sectional view taken through the tip of the spring piece.

Figure 6 is a perspective view of one of the springs.

Present day operations require accurate and complete cross sections of the coal or, other seams under consideration by means of diamond core drilling and recovery intact of cores. Due to the nature of the operations and the high water pressures involved, cores of relatively soft coal and the like are uniformly apt to be damaged or partially washed away out of the core barrel before they can be recovered; whereas in accordance with the present invention these difliculties are substantially eliminated and the recovery of of the barrel 5, as shown in Figure 2 of the drawings.

Within the outside core barrel 5 is the inside core barrel l0 whose lower end is externally threaded on the reduced and threaded upper end of the spring piece or core trap II, the threads usable cores can be expected with regularity even when drilling in the softer strata.

Referring. in detail .to the drawings, the numeral 5 generally designates the outside core barrel which is adapted to be rotated in a wellknown manner. The exterior of the outside core barrel is spirally grooved as indicated at 6, and its interior is smooth except for a short distance at its lower end where it is internally threaded as indicated at 1 to connect the diamond bit 8.

' The upper part of the bit is externally reduced and threaded at 9 to fit the threads I and bring the periphery of the bit flush with the exterior on the upper end of the spring piece being designated l2.

The spring piece ll comprisesa plain cylinder [3 having at its lower end the radially inwardly projecting. threaded flange I4. The cylinder [3 is imperforate and its plain cylindrical interior is interrupted only by a selected number, such as four, of equally circumferentially spaced longitudinal grooves or recesses l5 which extend from a point I6 near the upper end of the spring piece into the upper part of the threads 22 as at IS. The upper portions of the recesses l5 are gradually diminished upwardly in depth and finally feathered flush with the interior of the cylinder, the recesses being gradually deepened downwardly to a maximum depth at the top of the flange ll.

The recesses l5 have parallel sides just sufllciently spaced to movably accept the inverted laterally inwardly bowed leaf springs I! which are themselves of uniform width and lie along and work in the recesses.-

The upper ends of the springs I! have deflected terminals l8 providing a flat bearing against the floors of the recesses, while the lower ends of the springs having radially outwardly and downwardly deflected terminals [9. The lower terminals l9 flt closely in conformably shaped similarly angulated slots 20 formed through the wall of the cylinder I I, which slots the terminals 1111. In place the springs l1 bow inwardly as indicated in Figure 3 to holdingly engage the core (not shown).

The spring piece tip 20 temal flange 22 adjacent its upper end which threads into the flange l4 to'connect the tip it to the lower end of the cylinder H. The outer corner of the upper edge of the tip is beveled at 23 to provide an angulated rest and abutment for the springs II at points slightly spaced above the top of the flange l4 as shown in Figure 3 of the drawings, whereby the threading of the tip into the lower end of the cylinder positively locks the lower ends of the springs l1 securely in place in the slots 20. Obviously, unthre'ading of the tip'leaves' the lower ends of the springs free to be removed from the slots 20 and the springs as a whole to be removed from the cylinder II,

if desired.

has a threaded-ex The thus inverted springs l1 are arranged so that their upper terminals I8 are free to slide along between the sides of the recesses IS in response to flexing and elongation of the springs in action.

As shown in "Figure 2 of the drawings the plain cylindrical tip 2| depends into the upper part of the tubular diamond-bit 8 in concentrically spaced relation to its interior, to within say, onehalf inch from the fact 24 of the bit and acts as a guide for the core (not shown). This arrangement of the tip 8 acts to keep the pressure of the water off the core (not shown) while the springs hold the coreconcentrically in the inside core barrel, as the drilling operation proceeds,

Although I have shown and described herein a preferred embodiment of my invention, it is to be understood that limitation of the invention thereto is not intended except as may be required by the scope of the subjoined claims.

Having described the invention, what is claimed as new is:

1. In. a device of the character described, an outside core barrel having a bit at its lower end, an inside core barrel having a tube connected to depend from the lower end thereof, a tip threaded in the lower end of said tube and depending within said bit, said tube having substantially imperforate side walls, core seizing springs mounted in the interior of said tube, the lower ends of the springs being inserted in openings formed in the lower part of the tube, with the upper end of the tip holding the lower ends of the springs in said openings.

2. A device according to claim 1 wherein the upper ends of the springs are flattened to slidably engage longitudinal grooves formed in the interior of said tube.

3. A spring piece for a. core drill, said core drill comprising an outside barrel having a bit on its lower end and an inside core barrel depending into said outside barrel, said spring piece comprising a tube secured to the lower end of said inside core barrel and depending therefrom to a point adl'acent the lower end of the outside barrel, the lower end of said tube having an internally threaded portion of reduced diameter, a tubular tip having a beveled upper end and an externally threaded portion of enlarged diameter spaced below the beveled upper end, said externally threaded portion on the tubular tip being threaded in said internally threaded portion within the tube whereby the walls of said tip above said externally threaded portion are radially spaced from the wall of the tube, and longitudinally extending flat radially inwardly bowed springs in said tube above the tip, said springs having their upper ends slidably engaging the wall of said tube and having their lower ends inserted between the walls of the tip and the wall of the tube above said externally threaded portion of the tip, and means for securing said lower ends of the springs in place.

4. A spring piece according to claim 3 wherein said means comprises radially outwardly-deflected portions on the lower ends of said springs, said deflected portions being inserted in openings formed in the wall of said tube.

5. A spring piece according to claim 3 wherein said means comprises radially outwardly deflected portions on the lower ends of said springs, said deflected portions being inserted in openings formed in the wall of said tube immediately above said internally threaded portion in the tube.

6. A spring piece according to claim 3 wherein said means comprises radially outwardly deflected portions on the lower ends of said springs, said deflected portions being inserted in openings formed in the wall of said tube, said beveled upper end of the tubular tip bearing against the radially inward sides of the springs adjacent their lower ends.

OLIVER C. BARNETT. 

